Multiplex-telegraph system.



No. 797,570. PATENTED AUG. 22, 1905.

i T. GIARA. MULTIPLBX TBLEGRAPH SYSTEM.

APPLICATION FILED JULY 5, 19044 4 sHBBTs-sHBBT 1 No. 797,570. PATENTEDAUG. 22, 1905. T. GIARA. MULTIPLEX'TELEGRAPH SYSTEM.

APPLICATION FILED JULY 5. 100:1.

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T. GIARA. MULTIPLEX TELEGRAPH SYSTEM.

APPLICATION FILED JULY 5, 19042.

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No. 797,570. PATENTED AUG. 22, 1905. T. GIARA.

MULTIPLEX TELEGRAPH SYSTEM. Arrmowlou rILEn JULY 5. 1'904.

4 SHEETS-SHEET 4,

tions at the receiving-station.

TULLIO GIARA, OF BOSTON, MASSACHUSETTS.

WIULTIPLEX-TELEGRAPH SYSTEM.

No. '7er/,570.

Specification of Letters Patent.

Patented Aug. 22, 1905.

Application led July 5, 1904. Seria No. 215,222.

Be it known that I, TULLIO GIARA, oi' ABoston, in the county of Suii'olkand State oi' Massachusetts, have invented certain new and usefulImprovements in Multiplex -Telegraph Systems, oi' which the following isa speciiication.

This invention has relation to multiplex-telegraph systems, and has forits object to provide certain improvements therein by means oi which alarge number of messages may be sent over a sing'le line in bothdirections at the same time.

The invention contemplates the employment with each linewoil sendingapparatus and receiving' apparatus at each end thereof, the sending'4apparatus consisting' oi' a plurality oi' keyboards similar, iorinstance, to those of a typewriter, and the receiving apparatusconsisting of a plurality oi' separate printing mechanisms, cachprinting mechanism being similar to that of a type-writer.

Considering the invention in its simplest form, it consists of atransmitter having a single set of keys, a receiver comprising aprinting' mechanism' having' a single set of type-bars,v and a singleconductor or line, each ot' the transmitter-keys being' adapted to beelectrically connected by a branch circuit with one of a series ofcontacts or sections at the sending-station, and each printingkey beingsimilarly connected by a separate branch circuit with one of a series ofcontacts or sec- In the sending apparatus and in the receiving apparatusthere are movable brushes or contacts adapted to travel, successivelyover the stationary sections or contacts with which the sending'- keysor the printing-bars are severally Con nccted. Any suitable motive powermay be utilized tor eti'ecting the movement of the brushes or contacts,mechanism being employed for automatically synchronizing the movementot' the said contacts or brushes.

In order that the apparatus may be utilized -for sending messages inboth directions over the same conductor, there is on each end otl theconductor or line both a sending apparatus and a receiving apparatus,and in order that from each sending apparatus a number oi: messages maybe sent said apparatus includes a plurality or' keyboards and aplurality of sets of stationary contacts or sections, there being' ot'course a similar number of sets of type-bars or printing mechanisms at`the receiving' end, with an equal number oi' sets oi' sections orcontacts properly connected thereto. Preferably the stationary contactsor sections are arranged in series upon a iiat disk, over which themovablecontact travels in succession. In order that one operator may notinterfere with another operator in sending a message, means are providedby which the keys of each keyboard are locked against actuation exceptwhen the movable contact enters that segment of the disk in which arelocated the contacts for that particular keyboard.

As an extension of this invention there may be located upon eachsending-disk a plurality or' sets oi' contacts or sections for use inconnection with another line, there being corresponding sets of sectionsupon the receiving apparatus, with the proper number oi' keyboards andprinting mechanism for use in connection therewith.

It will be understood that in the employment of the term Lline theinvention is not limited thereby to a telegraphic system in which ametallic conductor is employed, Vfor the invention may be embodied inthe wireless system with equal facility, as will be subsequentlyexplained in detail, and by said term I therefore include any means forei'- Vi'ecting the transmission of an electrical impulse from thesending to the receiving apparatus.

Referring to the drawings, Figure l represents diagrammatically one formoi' telegraphic system embodying' the invention. Fig. Qrepresents thesame, but shows the disks which carry the commutator sections orconduits in side elevation and illustrates how the movable contacts aremounted and actuated. Fig. 3 represents an enlarged diagrammatic view ofthe sending and receivingl apparatus at one end of the line. Fig. 4represents diagrammatically the invention as embodied in the wirelesssystem.

It will be understood at the outset that I have not attempted toillustrate the apparatus in detail on account oi' the confusion thatwould result; but I have illustrated so much ot' the system as willenable one skilled in the art to embody the invention in practicallyworking form.

Referring to the drawings, l() l1 indicate two disks, which forconvenience I shall term, respectively, the Lsending and receiving disksand which are located at the stations A and B, respectively. On the disk10 are placed a plurality of sets of sections or stationary contacts,said sets being indicated at c, 7), c, d, e, and f, the contacts in eachset being insulated from each other and being indicated at 12. On thereceiving-disk 11 are similar sets of contacts or sections, which arerespectively indicated at g, L, v1, j, 1, and m, each insulated Sectionor contact being indicated at 13. The contacts or sections of each setof the sending apparatus are adapted to be connected by branch circuitswith the keys of the keyboard of a type-writing machine, so that thereare as many keyboards as there are sets of contacts upon the disk. In Fig. 1 two keyboards are illustrated fortwo different sections, theybeing conventionally shown by dotted lines at 1415. But one key is shownin each of the keyboards. as at 16 and 17, respectively; but as stateditwill be understood that in each keyboard there is one key for each ofthe sections or contacts in the set reserved for it on the disk.

Referring now to the receiving-disk atthe station B, it may be statedthat there is a single complete printing` mechanism for each set ofstationary contacts g It f, &c., two printing mechanisms beingconventionally illustrated by dotted lines, as at 18 and 19. Theseprinting mechanisms have not been illustrated in detail, there beingshown in each case a single type-bar 2O or 21. The sections or contacts13 of one set thereof on the disk 11 areconnected by branch circuitswith the several devices which actuate the respective type-bars of theprinting mechanisms. The type-baractuating mechanisms are illustratedconventionally as electromagnets 22, the coils .23 of which are inbranch circuits 24, connected, respectively, to the contacts or sections13. Re- Jerring once again to the sending-disk and its adjuncts, it willbe observed that each key 16 or 17 of the keyboards is adapted to closea circuit 2,5 from the source 26 of electricity to one of the contactsor sections 12. All of the branch circuits 25 may be connected with thesame source 26 of electricity.

27 represents an arm which rotates with a shaft about an axis concentricwith the disk 10. rlhe said arm carries a movable contact 28, which iselectrically connected by a conductor with a brush 29. From the brush 29a conductor 291 is connected to the coils of a duplex relay 31. One ofthe coils of said relay is connected electrically to the conductor,which in this case constitutes the main line 30, the other coil beingconnected with the artiicial line 701, which consists of the resistance71 and the condenser 70. At the otherend of the line 30 it is connectedto the coils of a duplex relay 32, there being another artificial line331, comprising a condenser 33, and a resistance 34, and grounded at 35.Each artificial line is equal in resistance and capacity to the mainline. The relay 32 is adapted to close a local circuit 36 at the stationB through a brush 37 on an arm 38, journaled on an axis concentric tothe disk 11. The said arm 38 rotates in synchronism with that at 27 andit carries a brush or movable contact 39, electrically connected withthe brush 37. As soon as this circuit is closed to the contact 39 thecurrent passes therefrom to a stationary contact or section 13, andthence through the conductor 24, effecting the energization ot' the coil23 therein and the actuation oi' the printing-bar 20. Consequently itwill be apparent that upon a depression at the sending-station of a key17 and the registering of the brush or contact 28 with the section orcontact 12, with which said key is connected, a current will pass outover the line 30 and close the local circuit 36 through the brush ormovable contact 39 to effect the actuation oi' a printing-barcorresponding to the key which was depressed. Assuming that the two arms27 and 38 are rotating in exact synchronism and at a rate of speed of,say, one hundred and fifty revolutions, more or less, per minute, itwill be seen that operators may work at all of the keyboards connectedwith the disk 10 and the signals will be successively transmitted overthe line 30 to eifect the actuation of the type-bars in the severalprinting mechanisms connected with the contacts or sections 13 on thedisk 11.

For the purpose of preventing the actuation of the keys of the keyboardsother than that in which the keys are connected with the set of contactsover which the movable contact 28 is passing locking mechanisms areprovided. Each mechanism consists of a pivoted lock 40, which normallyrests under the keys of the keyboard to prevent the actuation of thekeys. There is one lock for each keyboard and for each lock there is anelectromagnet 41, the coils of which are connected by a branch circuit42 with a segment 43 on the disk 10. There are as many of these segmentsas there are sets of stationary contacts or as there are keyboards, andthe segments are so located that when a movable contact 431 engages withone oi' the segments it closes the branch circuit through thecorresponding' electromagnet 41, which thereupon withdraws the lock fromunder the keys of the keyboard and permits the operator to depress theone upon which he has his finger, the keys of all the other keyboardsbeing locked at this time.

In order that messages may be sent in both directions, there is at eachstation' a sending apparatus and a receiving apparatus. At the station Athere is a receiving-disk 50, and at the station B there is asending-disk 51. The said sending-disk 51 is similar to that at 10, andit has a plurality of sets of stationary contacts, each set of contactsbeing connected with the keys of a separate keyboard. Two separatekeyboards are indicated conventionally at 52 53, and in each keyboardthere is illustrated.

a key 54. Fach key is adapted to close a branch l circuit to one of thecontacts, the keys all being connected in series with a source ofelectricity 56. On an arm 58, similar to that at 27, is a contact 57, inconstant electrical connection with a brush 59. Said brush is connectedby a conductor with a portion of the coils in the duplex relay 32 in thesame manner that the brush 29 is connected with the duplex relay 31. Thereceiving-disk 50 has a plurality of sets of stationary contacts, eachset of contacts being connected with the various actuatingmagnets 61 ofthe printing mechanism. The two printing' mechanisms are conventionallyindicated at 62 62, and in each there is represented a printing-bar 63.-Movable relatively to the disk is an arm 64, similar to that at 38, andcarrying a contact 65 in constant electrical connection with a brush 66.The said brush is connected to the switch 67 of the duplex relay 31,which closes the local circuit through said contacts 65, brush 67, andsource of electrical energy 68. The local circuit is indicated at 69.When a signal is sent from the disk 51 over the line 30, it divides andpasses `through all of the coils of the duplex relay 31 and into acondenser 70 and through resistance 71 to ground and also to the mainline 30. From this explanation it will be apparent that when a signal issent from the disk 10 the current traverses the coils of the relay 31and divides into two equal parts, one of them going to the groundthrough the resistance and the capacity and the other going over theline to the duplex relay 32. The switch 321 of the relay 32 closes thelocal circuit 36 through the proper contact of the receiving-disk 11. Asthe current passes over a line it has no ei'ect upon the switch 67 atthe station A. In the same manner when a signal is sent'from thesending-disk 51 of the station B it produces no effect on the duplexrelay 32, but causes the closing of the local circuit 69 at the stationA.

' At the station B it will be understood that the disk 51 has segments711 corresponding to those at 43 on the disk 10, the said segments beingarranged in multiple with relation to each other, but connected inseries with a source of electricity 72. Each segment is in a branchcircuit 73, in which there is placed an actuating-magnet 74 for thekey-lock 75, which key-lock corresponds to that at 40, which washereinbefore described. Assuming now that all ot the arms 27, 38, 58,and 64 are rotating in synchronism and that the sending and receivingdisks are properly related, it will be apparent that at each of thestations there may be as many operators sending as there are keyboards.The speed at which each operator may send his messages is limited by thenumber of rotations per minute of the traveling contacts, since anoperator may send an impulse representing one character over the lineonly when the arm of the sending-disk is on the segment 43 correspondingto the keyboard upon which he is operating; or, in other words, he cansend one impulse foreach revolution ot' the arm. v

Means are provided for effecting the syn- -chronous movement or' thearms 27, 38, 64,

.cal motor to which current is supplied by a circuit 83. The two disks10 and 50 are attached to an upright 84, in which the shaft is journaledThe two arms 27 and 64 are secured to the shaft so as to rotatetherewith, each of the arms having' a hub against which the stationarybrush 29 or 66 acts, as best shown in Fig. 2. At the station B the twoarms 38 and 58 are'secured to a shaft 85, being journaled in an upright86, to which the disks 51 and 11 are attached.

It will be observed that on the sendingdisk 10 there is, between eachadjacent set of stationary contacts, an additional contact 90, which maybe engaged by the brush 28 on the movable arm which sweeps around thedisk. On the said disk 10 the contacts are all connected in multiplewith a circuit A 91 in series with a battery or source ot' power 26, sothat each time the brush 28 engages one of the contacts 90 an impulse issent out over the line 30. At the receiving-disk 11 there are twoinsulated contacts 92 93, placed between each adjacent pair of the sets`g t, &c., of stationary contacts 13. The contacts 92 are connected inmultiple with a circuit 94, and the contacts 93 are connected inmultiple with the circuits 95. The circuit 94 includes an electromagnet941, and the circuit 95 includes an electromagnet 951, each oi' thecircuits then grounding, as indicated. vWhen an impulse comes over theline 30 to the brush 39, (it being assumed that the arm 38 is moving insynchronism with the arm 27,) the current will pass from the brush 39and divide into the circuits 94 and 95; but if the arm 38 lags or is inadvance of the arm 27 the current will flow into either one or the otherof said circuits. This is forthepurpose ot accelerating or retarding themotor which drives the arm 38, as will be now explained.

The arbor 85 is driven by a motor 100, there being a momentum-wheel 101,as shown in Fig. 2. ,This motor is preerabl y electrical and receivesits current from a circuit 102. The said circuit includes a stationarycontact 103, a switch 104, a movable contact 105, and a rheostat orvariable resistance 106, as shown in Figs. 1 and 2. The switch 104 isunder the control ot' an electromagnet 107, placed in a branch circuit108, connected in series with the duplex relay-switch 321 and groundedat 110. lhc movable contact 105,

which coacts with the resistance or rheostat 106, is under the controlof the two electromagnets 941 951 and is adapted to be moved in onedirection or the other, thereby to throw in or throw out more or less ofthe resistance-coils of the rheostat 106 to eifect a variation in thespeed of rotation of the armature of the motor 100. Each time that animpulse is transmitted over the line 30 to the station B the duplexrelay 32 is energized to close the local circuit 36 through the brush37, the contact 39, and one of the printing-bar-actuating magnets 23`and at the same time, however, a portion of the impulses passes throughthe branch circuit 108 and through the electromagnet 107 to close themotor-circuit 102. These impulses over the line 30 follow each other sorapidly that the residual magnetismin the magnet 107 serves to keep theswitch 104 closed practically all the time, and therefore the arbor 85,which carries the arms 38 and 58, will be constantly rotated. Vhen thearm 27 of the disk 10 at the station A and the arm 38 otl thereceiving-disk 11 ot' the station B are rotating in exact synchronism,the impulses sent over the line 30 by the engagement of the contact 28with the stationary contacts 90 will have the eiect of causing theimpulse set up in the local circuit 36 to divide, a part of the currentpassing out from the contacts 93 over the circuit 95 to theelectromagnet 951 and a part passing out through the contacts 92 throughthe circuit 94 to the electromagnet 941, in consequence ot' which thetwo electromagnets 951 and 941 will oppose each other and there will beno action of the movable contact 105; but should the arm 38 lag orshould it slightly increase in speed relatively to the arm 27 all of thecurrent wou-ld pass out through the vstationary contacts 92 or 93, asthe case may be, to cause the movement of the rheostat-lever 105 in onedirection to reduce the resistance or else in the other direction toincrease the resistance, and thereby accelerate or retard the speed ot'rotation of the armature of the motor 100 and ot' the arbor 85. Fromthis description it will be apparent, therefore, that the speed otrotation of the arbor 85 will be automatically regulated and thecontact-arm 38 thereon be caused to rotate in synchronism with the arm27 on the sending-disk. The arm of the sending-disk 51 at the station Bis on the arbor 85, and the arm 64 or' the receiving-disk 50 at thestation A is on the arbor 80, so that the said arms 58 and 64 will becaused to move in synchronism by the means just described. As it mighthappen that the two motors Jfor rotating the arbors 80 and 85 might notstop at the same point when the apparatus is permitted to come to astate of rest, it is evident that provisions must be made for adjusting'the receiving-disks about their arbors.

Some signal is selected for the purpose of testing the apparatus. Forinstance, the key representing the character X7 in the keyboard for thecontacts o in the sending-disk 10 is depressed by the operator and asignal is sent over the line. This has the effect of starting the motor100. Then the operator at the station B rotatively adjusts the disk 11until the type-writing machine connected with the series g of contactson the disk 11 (which corresponds to the series a of contacts on thesending-disk 10) prints the letter X. The sending operator at B sendsout a similar sig'- nal to the receiving operator at the station A, whoadjusts the disk 50 until the signal X is transmitted to the properprinting mechanism and the proper type-bar is actuated. The apparatus isthen ready for the transmission of messages.

The mechanical details ot' construction of the apparatus have not beenillustrated, since they may vary greatly and may he made to suitparticular requirements. For instance, the keyboards which are utilizedfor sending the messages are preferably those of a type-writing machine,so that the sending operator not only sends the messages over the line,but prints them on the type-writing machine that he may preserve anaccurate record of the message which he has sent. Similarly the printingmechanisms connected with the receiving-disks are all of suitablecharacter, such as type-writing machines in which the carriage isautomatically shifted and the platen automatically moved at the propertime.

As stated at the outset, the invention may be embodied inwireless-telegraph systems, as illustrated in Fig. 4. The apparatus atonly one station is illustrated. `The sending and receiving disks andtheir connecting' electrical and mechanical mechanisms are similar tothose previously described, the means for ei'- iecting the synchronousrotation of the contact-arms being no ditierent from that hereinbeforeexplained. Instead of the continuous conductor 30 there is at thestation a mast 200, having antenna 201, which may receive the impulsessent from a mast at the other station. I will iirst explain how themessages are sent out from the mast 200. The conductor 202, whichcorresponds to the conductor 291 Jfrom the brush 29 in the system shownin Fig. 1, is grounded at 203 and is connected with an electromagnet204. This electromagnet controls a switch 205 for closing a circuitwhich includes the said switch, a source of electric energy 206, and theprimary 207 of an' induction-coil. The secondary 208 of the said coil isin a circuit 209, which includes the oscillator 210 and another primary211. The last-mentioned primary 211 is placed in inductive relation to asecondary 212 in a circuit 213, one end of which is grounded at 214 andthe other end of which is connected to the antenna 201. This is theusual arrangement of circuits in wireless telegraphy for sending animpulseto the antenna to be dischargedinto the atmosphere. The circuit213 includes the usual resistance 215. From this description it will beseen that each time a key in one ol' the keyboards of the sending appaatus is depressed a signal is discharged lfrom the antenna. Thereceiving' apparatus will now be explained. The switch 104 correspondsto that indicated by the same numeral in Fig. 1, andY it controls themotor-circuit 102, as previously explained. The local circuit 36 108 islikewise the same as pres Viously described; but the switch 321,corresponding to that indicated by the same numeral in Fig. 2, is underthe control of an electromagnet 220 instead of the duplex relay. Thesaid magnet is placed in a local circuit 221, including a battery orsource of power 222. Said local circuitincludes a coherer 223, tworesistan'ces 224, and the coils 225 of the jigger. The said coils 225are arranged in inductive relation 'to a coil similar to that at 202 ofthe local circuit 218, previously described. rI`he usual condenser 226is located, as ordinarily, between coils 225 225, as shown. When animpulse is received at the antenna 201, it acts through the jigger 225upon the coherer 223, whereupon the circuit 221 is momentarily closedand an impulse is received in the local circuits 36 and 108. Theprinting mechanism is properly actuated in the same manner ashereinbefore described in de tail.

In order that a single sending apparatus may be employed for sending'over more than one main line and be therefore utilized for transmittingmessages to two or more relatively remote receiving-stations, eachsending-disk may be equipped with more than one series ol sets ofstationary contacts, as illustrated in Fig. 1, where the disk 10 as asecond series (indicated as a whole at ai) is arranged concentricallywithin the series comprising the sets (t L c, te. The arm 27 has asecond contact 400, which coacts with the contacts of the series fr, andthere is a second circuit 401, with whichthe contact 400 is connected bythe brush 402 and which corresponds with that at 291 and forms a partoi' a second main line. (Not shown.) Each set oi' contacts of the seriesfr has its separate keyboard or type-writing machine and also has thesynchronizing contacts, as previously described, which coact with theother elements of the motor-controlling mechanism.

To permitone receivingapparatus to be employed in connection with thesendingdevices at relatively remote stations, the receivingdisk, as at11, may have a plurality of series of sets ol contacts, as at 405, withwhich a contact 406 on the arm 38 may coact. The

contact is connected by al brush 407 with a local circuit 408 similar tothat at 36 and controlled by signals on a main line like that at 30. Theseries oiI contacts 405 will of course be connected with the properprinting mechanisms, as previously described.

It will be understood that many and various changes may be made in thehereinbefore-described system without departing ro'm the spirit andscope of the invention.

Having thus explained the nature of the invention and described a wayot' constructing and usingthe same, although withoutattempting to setforth all of the forms in which it may be made or all of the modes ofits use, I declare that what I claim is 1. In amultiplex-telegraphsystem, a main line, a plurality ot' key-circuits each connected to asource of electrical energy and having a contact, a revolving contactJor successively engaging said contacts respectively and connected tothe line, so thatwhen a key is moved to close its circuit, an electricalimpulse is sent over the line upon the engagement of the movable contactwith the stationary contact in said key-circuit. a plurality oi'printing-circuits, each having a printing device, and each having acontact, a second revolving contact connected with a source ofelectrical energy, and adapted to successively engage the lastmentionedcontacts, a relay in the main line for closing the circuit through saidlast-mentioned revolving contact and thereby through one of theprinting-circuits when a signal is sent over said main line by any oneof the keycircuits, a motor for revolving the revolving contact at thesending-station, an electric motor for revolving the revolving contactat the receiving-station, and means for synchronizing the movement ofsaid revolving contacts, by automatically varying the speed of saidelectric motor.

2. In a multipleX-telegraph system, a main line, a plurality ot' setsot' key-circuits each connected to a source of electrical energy havinga contact, the contacts of said sets being arranged serially in acircle, a revolving contact for successively engaging the said contactsand connected to said main line, a plurality of sets ofprinting-circuits each having a printing device and a contact, thelast-men tioned contacts of said sets being arranged serially in acircle, a second revolving contact connected to a source of electricalenergy and adapted to successively engage said last-mentioned stationarycontacts, means controlled bythe main line for closingthe circuitthrough said second revolving contact, means 'for revolving saidrevolving contacts, and means for preventing the closing olf thekey-circuits of the other sets thereolI when the first-inentionedrevolvingcontact is in engagement with the contacts of the key-circuitsot' any one set.

3. In a system of the character referred to, the combination ot' tworevolving contacts, means Vlor revolving one of said contacts, anelectric motor `for rcvolif'ing the other contact, an energy-varyingdevice for the motor-circuit having movable contacts, electromagnets foractuating the movable contacts of said device, separate circuits forsaid electromagnets, and means controlled by both of said revolvingcontacts for diverting' current into said electromagnet-circuits.

4. In a multiplex-telegraph system, sending apparatus comprising aplurality of different series of sets of contacts, a key connected toeach contact to close a circuit thereto, an independent line for eachseries of sets of contacts, and a movable element having insulatedcontacts electrically connected to said independent lines for engagingthe contacts of said respective series of sets.

5. In a multiplex-telegraph system of the character described, aplurality of independent contacts symmetrically disposed in a circle atthe sending-station; a source of electricity connected to said contacts;a multiple number of independent contacts symmetrically and identicallydisposed in groups in a circle at the receiving-station; a revolving'contact at the sending-station; a motor for revolving said contact; arevolving contact at the receivingstation, an electric motor forrevolving said last-mentioned contact; a motor-circuit; means forvarying the energy of the current in said circuit; and electricalconnections between said groups of contacts at the receiving-station andsaid energy-varying means, in consequence of which the speed of theelectric motor is caused to vary to synchronize the revolution of saidrevolving contacts.

6. In a multiplex-telegraph system of the character referred to, anumber of independent contacts symmetrically disposed in a circle at thesending-station, a source of electricity connected to said contacts; amain line; a revolving contactfor engaging said independent contacts andconnecting them to the main line in such manner that from them electricimpulses go over the line to a receiving-station; means for moving' therevolving' contact; a revolving contact at the receivingstationconnected to a source of electrical energy, an electric motor forrevolving said revolving contact; a number of electrical resistances inseries in the motor-circuit, a multiple number of independent contactssymmetrically disposed in groups in a circle at the receiving-station,each contact of the groups being connected to an electromagnetcontrolling one of the electrical resistances in the motor-circuit, insuch manner that an impulse sent by an independent contact of thesendingstation arrives at the receiving-station at one of the contactsof agroup and energizes the corresponding' electromag'net which insertsin or cuts out of the motor-circuit the corresponding resistance.

7. In a multiplex-telegraph system, a single main line, a plurality ofsending' devices at the sending-station, each including a keyboard witha plurality of keys, a plurality of printing mechanisms at thereceiving-station, each printing mechanism having types correspond-l ingto said keys, and electrical connections including said single main linebetween said devices and said stations in consequence of which upon theindependent manipulation of the keys in the different keyboardselectrical signals are successively transmitted from the sending devicesto the said printing mechanisms over the same line, to cause theactuation of the corresponding' types in the corresponding printingmechanisms, and the printing of different messages by said printing'mechanisms.

8. In a multiplex-telegraph system, a single main line, a plurality ofindependent keyboards at the sending-station, each keyboard having aplurality of independent keys, a source of electricity for said keys, aplurality of printing mechanisms at the receiving-stations correspondingto said keyboards, each printing mechanism having a separate movable type-bar for each separate key of the corresponding keyboard, and meansfor connecting the keys of the keyboards and the corresponding' type-barof the corresponding printing mechanisms, successively, with said singlemain line, whereby different messages equal in number to the keyboardsmay all be sent over the single main line and printed at substantiallythe same time.

9. In a multiplex-telegraph system, a main line, a series of independentkeyboards each having a set of keys, a plurality of sets of keycircuitseach connected to a source of electrical energy vhaving a contact, thecontacts of said sets being' independent of each other but arrangedsuccessively in a circle or arc thereof, a revolving contact forsuccessively engaging the said contacts of the different sets andconnected to said main line, a plurality of independent sets ofprinting-circuits each having' an independent electromagnet actuating atype, and a contact, the last-mentioned contacts of said sets beingarranged successively in a circle, or in an arc thereof, a secondrevolving contact connected to a source of electrical energy and adaptedto successively engage said last-mentioned stationary contacts, meanscontrolled by the main line for closing the circuit through said secondrevolving contact, and means for revolving said revolving contacts, saidelements being arranged as described, whereby impulses for the dierentsets of keys are sent successively over the line.

l0. In a multiplex-telegraph system, a plurality of independent sets ofkey-circuits at the sending-station each connected to a source ofelectrical energy having a contact, the contacts of said sets being'arranged successively in a circle or the arc thereof, a main line, arevolving contact at the sending-station for successively engaging saidindependent sets of contacts, and connected to said main line; aplurality of independent printing' mechanisms at the receiving-stationeach having an independently-movable type-bar for each character,circuits equal in number to the type-bars, and each having anelectromagnet for controlling a type-bar, and a contact, said contactsbeing arranged in sets successively ina circle; a revolving Contact atthe receiving-station connected to a source of electrical energy andadapted to successively engage the sets of contacts at thereceiving-station, means controlled by the line for closing the circuitthrough said second revolving- Contact, and means for revolving saidrevolving contacts. In testimony vvhereo` I have alXe-d rny sig naturein presence of two witnesses.

TULLO GIAHA. lVitnesses:

(.- C. STECHER, VALTER P. ABELL.

